How to Create Multi Sine FM Deep Bass Synth Sound With FL Studio Sytrus

Sytrus is great for all kinds of synth sounds but it's especially good for bass. Gary Hiebner walks you through creating a heavy bass patch.  

What I really like about Sytrus is not only can you create awesome punchy lead sounds with it, but you can also use multiple operators together to create a deep and thick FM Bass sound. In this tutorial I’m going to show you how to create a bass sound like this by using multiple sine operators and modulating them together to get an even thicker sound. Let’s jump in and see how this is done.

Sytrus Default Patch

First let’s add Sytrus to a channel track, and load up the default Sytrus patch. You can do this by right-clicking on the arrows that switch through the presets. This will bring up the preset contextual menu, and then choose ‘Default’ at the top. This patch will now be a single Sine operator sound.

The First Sine

For the first operator I’m going to keep it as a sine wave and tune the frequency ratio down to 1.0000x. This is really just a simple sine wave tuned lower down. But the magic starts happening when I add another sine wave and modulate it to the first operator. 

The Second Sine

On to the second operator. I’m going to add another sine wave, but on this one I’m going to change the frequency ratio to 4.000x. So this sound will be 1 octave up from the first sine operator sound. Now I want to modulate the first operator with this, so on the modulation matrix I’m going to go to the second operator on the first line and increase the value slightly. Now you’ll hear how the one sine wave is modulating the other. You don’t need a huge amount to hear it. Subtlety is key here but the beauty is in the FM modulation of these sine waves. Extra harmonics get introduced and you get a more complex sound. 

Envelope Modulation

Now the key to getting that deep bass sound is to apply some envelope modulation. So make sure the Mod section is selected below, and then the Env below this. And then enable the ADSR at the bottom. Now take a listen when you increase and decrease the Attack how it alters the sound. I quite like it with a short attack so it’s nice and punchy.


Add Unison

Now to beef up the sound a bit more move over to the Main Tab and add some Unison. I’ve set my Unison order to 9 and have also increased the Unison Sub Level. This dials in more voices on this sine patch. So it’s a great trick to use to thicken up the sound more. 

And what also works quite well is to increase the Unison Phase, it adds some more depth to the sound with this phasing.

The Third Sine

For the heck of it, let’s add another sine waveform on to operator 3. And this time use an 8.0000 x freq ratio. So this operator with be 2 octaves higher than the first operator. Now modulate this operator in the matrix window with operator 1. Hear how the modulating sine operators are really giving a nice deep and complex sound now.

Also try modulate the third operator with the second instead of the first and hear the results. So, it’s amazing how far 3 simple operators can go when combined with FM synthesis in this modulation matrix on Sytrus. 

You can enable the ADSR on all the operators and tailor how you want the attack to sound on each of them, giving you a varied transient attacks to the sound. Now this deep bass sound can be used across a multitude of different genres. And you can even layer it up against the bass you already have in your track to give some extra low end to the sound.

Adding in Filters

What’s quite nice as well is to add some filters into the mix. I’m going to turn off the output volume for operator 1, then I’m going to route operator 1 to Filter 1. I’ll dial in amount of 40%, and then I’ll turn up the volume on its output level.

Then I’m going to use a LP3 filter (the Mango Low Pass Filter, I really like this one as it has an awesome filter curve shape and some drive that can be added into the filter). I’ll dial in a Cutoff of 50%, a Resonance of 25%. I’ll dial the Drive back to about 64%. I’ll leave the Env set at 50%. I can also enable the ADSR on the Cutoff Envelope and tweak the attack times to get a punchier sound.

Now what I can also do is add the output of operator 1 back in this mix. This gives me control over the volume for the FM modulated operators, plus the volume from the filter they pass through. So I can mix these outputs together to get a balance of the bass sound I want.

Adding Effects

And to finish it off let’s add some slight effects to the sound. So choose the FX tab, and I’m going to add a touch of reverb to give the bass sound a space it belongs in. For the Color I’m going to use the W+, which is the warmer preset. And then on the modulation matrix I’m going to apply it to my second operator line. So I’ll increase the effects amount here to about 20%. 


That’s how to create a Multi FM Sine wave bass synth sound with Sytrus. This creates a really deep and complex bass sound that can complement an array of genres to emphasize the bass, or add an extra character to it. So try this out in Sytrus in your next project and see if it helps reinforce the low end in your song.

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Gary Hiebner is an enthusiastic South African Sound Designer and Apple Tech Head! Gary has been involved in the South African music industry for the decade, and in this time has also been involved in the sound design and music production for many advertising agencies and media houses. Gary is a devoted Logic and Ableton user, but he al... Read More


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